ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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effect in dimini sting the diametral growth of the trunks, but not in the 
length of the shoots, at all events in some kinds of tree. 
Development of Buds.* * * § ' — According to Herr P. Albert, out of 15 
kinds of trees examined in which the leaf-buds are provided with scales, 
the formation of the leaf began, in 1 species, in May of the year preced- 
ing the unfolding, in 3 species in June, in 8 in July, in 2 in August, 
and in 1 in September. The period of the commencement of the 
formation of the flowers or inflorescence varies from May to September. 
In those trees in which the leaf-buds are not enclosed in scales, the 
formation of the leaf commences in some instances in the year before 
the bud makes its appearance, in others in the year before it unfolds. 
Nutrition of Plants by Humus, f — From a series of experiments, 
made chiefly on Poa annua , M. E. Breal concludes that potassium 
humate is absorbed directly by plants, without the intervention of lower 
organisms. 
Periodicity in the Formation of Roots.J — Herr A. Wieler has 
investigated the connection between the unfolding of leaves and the 
formation of roots. In all the species of trees examined he finds the 
same law to prevail — that the formation of roots is coincident with that 
of leaves, or may begin earlier ; it scarcely ever continues longer. 
Germination of Lathrsea.§ — Prof. E. Heinricher has succeeded in 
germinating the seeds of Laihreea clandestina. The process is a very 
slow one, and takes place only in the presence of woody Dicotyledons, 
such as Corylus , Alnus, and Salix. The growth of the seedling is exceed- 
ingly slow. 
Protection of Chlorophyll. || — Prof. J. Wiesner describes the different 
fixed positions assumed by the leaves of tropical trees (Java) in relation 
to the incident light, and the various contrivances for the protection of 
the chlorophyll against the destructive effects of excessive insolation. 
These latter are chiefly two — the formation of anthocyan in the cells, 
and the permanence of an unturgid condition enabling the leaf to hang 
in a vertical position. 
Ascent of Sap.1T — Mr. H. H. Dixon and Dr. J. Joly have investigated 
the capability of the leaf to transpire against excessive atmospheric 
pressure; the results lead them to believe that the draught upon 
the sap established at the leaf during transpiration is alone quite 
adequate to effect the elevation by direct tension of the sap in tall 
trees. They also draw the conclusion that the ascent is principally in 
the cell-cavity and not in the cell-wall. 
* Forstlich-naturw. Zeitschr., iii. (1894) pp. 346-76, 393-419. See Bot. Cen- 
tralbl., lxi. (1895) p. 228. 
t Ann. Agron., xx. (1894) pp. 353-70. See Journ. Chem. Soc., 1895, Abstr., 
p. 28. Cf. this Journal, i894, p. 478. 
t Forstwissensch. Centralbl., xvi. (1894) pp. 333-49. See Bot. Centralbl., lxi. 
(1895) p. 21. 
§ Ber. Deutsch. Bot. Gesell., xii. (1894) Gen.-Vers.-Heft, pp. 117-32 (1 pi.). Cf. 
this Journal, 1893, p. 500. 
|| SB. Akad. Wiss. Wien, ciii. (1894) pp. 8-36. Cf. this Journal, 1894, p. 475. 
If Ann. Bot., viii. (1894) pp. 468-70 ; Proc. Roy. Soc., lvii. (1895) pp. 3-5. 
